new

print("enter diameter")
size = read()
size = tonumber(size)

x,y,z = 0, 0, 0

function forwardOnce()
  for i = 0, size -1 do
    if turtle.detect() then
      turtle.dig()
      turtle.forward()
    else
      turtle.forward()
    end
  end
end

function digForward()
  for i = 0, size-2 do
    if turtle.detect() then
      turtle.dig()
      turtle.forward()
    else turtle.forward()
    end
  end
end

function turnRight()
  turtle.turnRight()
  turtle.dig()
  turtle.forward()
  turtle.turnRight()
end
function turnLeft()
  turtle.turnLeft()
  turtle.dig()
  turtle.forward()
  turtle.turnLeft()
end

function main()
  forwardOnce()
  for i=0, size-2 do
    if (i % 2) == 0 then
      turnRight()
      digForward()
    else
      turnLeft()
      digForward()
    end
  end
end

main()